The present invention relates to an improved process for the production of coke, particularly for metallurgical purposes.
It is known to produce coke in an indirectly heated, discontinuously operated chamber oven. Specifically, it is known to form briquettes, particularly molded briquettes of pitch-bound coal, to introduce such briquettes into a coking chamber of an indirectly heated chamber oven, and to then coke the briquettes within the chamber of the oven to form coke. Such known process is described, e.g. see "Stahl und Eisen" 1972, pages 149 and 150; "Colliery Guardian Annual Review" 1974, page 54 and "Gluckauf-Forschungshefte" 1975, page 148. However, when producing coke by this known method, there invariably occurs the inherent disadvantage that the formed coke tends to cake during the coking operation, i.e. the pellets of coke formed from the initial briquettes tend to cake or stick together. This results in the operational problem of the caked coke being difficult to remove from the oven chamber after the coking operation, and further results in the quality control problem of unsatisfactory coke quality.
One attempt to overcome these problems of the known coke forming process is disclosed in German patent application No. P 26 13 711.1-24, wherein the molded briquettes are formed to have a particular surface area to volume ratio related in a particular manner to the interior width of the oven chamber, and wherein when employing chambers having relatively larger widths relatively large size molded briquettes are employed, and inversely when employing chambers having relatively small widths relatively smaller sized briquettes are employed.
Specifically, the process of such German patent application employs the use of molded briquettes formed according to the relationship: EQU k=0.5-O.sub.B /V.sub.B .times.(1-e).times.B,
wherein: k equals the ratio between the total surface area of the briquettes contacting the interior walls of the chamber to the total surface area of the interior walls; O.sub.B equals the surface area (in m.sup.2) of a briquette; V.sub.B equals the volume (in m.sup.3) of a briquette; e equals the ratio between the total volume of the gaps or empty spaces between briquettes in a pile or charge of briquettes in the chamber to the total volume of the charge of briquettes; and B equals the width (in meters) of the chamber.
The invention of such German patent application is based upon the discovery that for every chamber of a given interior width there exists at a given heat flow a particular molded briquette size at which, during the coking operation, the briquettes and formed coke are neither caked nor deformed, such that the desired quality of coke is achieved while the oven chamber may be easily emptied after the coking operation. Accordingly, based on the discovery of the German application, there exists an optimum size of molded briquettes for a given chamber width, and inversely there exists an optimum chamber width for a given size of molded briquettes, whereat caking of the briquettes and formed coke during the coking operation is reduced.
It has however been found that even when employing the process of the above German application, there still occurs some caking.